Yesterday I started the #mail #migration using #KMail #import tool and targeting #thunderbird profile folder.
Please note that I use Thunderbird since 15 years as my favorite mail client, and I used to have 5 or 6 accounts (plus my daugthers' accounts for school). So the amount of emails to migrate, even though I'm convinced that only the essential was left, was huge... ~92 GiB!!!
Now... I feel I need to reboot my #Debian, that looks a bit unstable after 1 full day spent crawling and indexing old emails... and then start Kmail... wish me good luck!